@Chrona @phil777 a soldier who's been shot in a life threatening location takes up ridiculous amount of resources.
You have to risk transport to bring them out of the immediate battle. You have to arrange transport to a safe medical centre. At that point he is is effectively out of the fight for 6-10 months on average, during which the state has to look after him if he survives, and if he needs to have limbs amputated or organs removed, he likely can't go back to fight again at all. The country needs to care for him, provide medical attention, and have doctors run ragged the more casualties there are.
And you have the bad press of the soldiers screaming in agony, young men and women permanently maimed, blinded, choking on their own blood, having to shit in a bag, scorched faces like undercooked beef.
A corpse takes five minutes of work by a couple of soldiers to bury. A wounded soldier takes the equivalent of five men off the front line for a few weeks.
Hospitals are there to stop people dying. They aren't some magical unit healing facility that lets you turn injured soldiers into fighting soldiers again. Destroying them really doesn't help reduce the enemies you need to subdue to win.
What it DOES do is demoralise the enemy troops, since if they get shot, they will probably die without hospitals to help them. But hospitals don't actually help get very many soldiers back to the front line.
Now in magical healing land, none of that applies and shooting the healer is fair game. But mysteriously we don't have magical healing spells in real life.